The purpose of the project is to promote research on historical trends and, in particular, interstate variations in the mortality of the United States since the 1930s. To this end, we will construct a publicly-accessible collection of mortality data series by state, designed to meet the research needs of team members and collaborators as well as those of the greater academic community. The new data series will include indicators of both total (i.e., all causes of death) and cause-specific mortality. We will create state-level estimates of all-cause mortality by age, sex, and year for the period from 1933 to 2007. We will also create annual state-specific estimates of mortality by age, sex, and cause of death for 1959-2007 (possibly, 1950-1958 as well). All data series will have the same format used for country estimates in the Human Mortality Database (HMD, www.mortality.org), helping to facilitate comparative research both within the United States and on an international level. This work will draw on data from various sources, including the vital registration system, the decennial census, and the beneficiary records of Social Security and Medicare. It will require the development of new methodologies for combining such information into coherent and comparable series of mortality estimates, including complete life tables. Our knowledge of the data sources, including their defects and limitations, will be clearly documented and distributed alongside the data within the HMD. The project is intended to catalyze research on mortality patterns and trends by state within the U.S. State-specific mortality data are intrinsically useful for the analysis of health disparities, since geographic differences are an important component of overall inequality in the face of death. The products of the work proposed here will facilitate more detailed analyses of regional mortality differentials by cause within the U.S., which could offer new insights and evidence about the driving forces behind the country's mortality trends in recent decades - in particular the slow pace of decline compared to other high-income nations, especially for women.